Rilonacept and Anakinra in Recurrent Pericarditis: A Systematic Review and Meta-Analysis

Interleukin 1 (IL-1) has been indicated as a mediator of recurrent pericarditis. Rilonacept, a soluble IL-1 receptor chimeric fusion protein neutralizing interleukin 1 alpha (IL-1α) and interleukin 1 beta (IL-1β), has demonstrated promising results in a phase II study in recurrent or refractory pericarditis. Anakinra is a recombinant inhibitor of the IL-1 receptor with a demonstrated reduction in the incidence of recurrent pericarditis. Definite pharmacological management of pericarditis is key to preventing recurrences, mostly treatment options for recurrent pericarditis refractory to conventional drugs. Here we critically discuss the existing therapy options for recurrent pericarditis, with a focus on new pharmacological approaches: rilonacept and anakinra. A systematic search was conducted across online databases such as PubMed, Cochrane, Google Scholar, ScienceDirect, CINAHL, Scopus, and Embase to obtain clinical trials that assess the effectiveness of anti-interleukin 1 therapy such as anakinra and rilonacept in the management of recurrent pericarditis. Our study concluded that anti-interleukin 1 therapy significantly improved both the quality of life and the clinical outcomes of the study population. These outcomes were most prominent with the use of rilonacept and anakinra in the trial treatment. Rilonacept and anakinra are valuable options in case of recurrent pericarditis refractory to conventional drugs

Protein Kinase C Activation Has Distinct Effects on the Localization, Phosphorylation and Detergent Solubility of the Claudin Protein Family in Tight and Leaky Epithelial Cells

We have previously shown that protein kinase C (PKC) activation has distinct effects on the structure and barrier properties of cultured epithelial cells (HT29 and MDCK I). Since the claudin family of tight junction (TJ)-associated proteins is considered to be crucial for the function of mature TJ, we assessed their expression patterns and cellular destination, detergent solubility and phosphorylation upon PKC stimulation for 2 or 18 h with phorbol myristate acetate (PMA). In HT29 cells, claudins 1, 3, 4 and 5 and possibly claudin 2 were redistributed to apical cell–cell contacts after PKC activation and the amounts of claudins 1, 3 and 5, but not of claudin 2, were increased in cell lysates. By contrast, in MDCK I cells, PMA treatment resulted in redistribution of claudins 1, 3, 4 and 5 from the TJ and in reorganization of the proteins into more insoluble complexes. Claudins 1 and 4 were phosphorylated in both MDCK I and HT29 cells, but PKC-induced changes in claudin phosphorylation state were detected only in MDCK I cells. A major difference between HT29 and MDCK I cells, which have low and high basal transepithelial electrical resistance, respectively, was the absence of claudin 2 in the latter. Our findings show that PKC activation targets in characteristic ways the expression patterns, destination, detergent solubility and phosphorylation state of claudins in epithelial cells with different capacities to form an epithelial barrier

ADAM15 mediates upregulation of Claudin-1 expression in breast cancer cells

A Disintegrin and Metalloproteinase-15 (ADAM15) is a transmembrane protein involved in protein ectodomain shedding, cell adhesion and signalling. We previously cloned and characterised alternatively spliced variants of ADAM15 that differ in their intracellular domains and demonstrated correlation of the expression of specific variants with breast cancer prognosis. In this study we have created isogenic cell panels (MDA-MB-231 and MCF-7) expressing five ADAM15 variants including wildtype and catalytically inactive forms. The expression of ADAM15 isoforms in MDA-MB-231 cells led to cell clustering to varying degree, without changes in EMT markers vimentin, slug and E-cadherin. Analysis of tight junction molecules revealed ADAM15 isoform specific, catalytic function dependent upregulation of Claudin-1. The expression of ADAM15A, and to a lesser degree of C and E isoforms led to an increase in Claudin-1 expression in MDA-MB-231 cells, while ADAM15B had no effect. In MCF-7 cells, ADAM15E was the principal variant inducing Claudin-1 expression. Sh-RNA mediated down-regulation of ADAM15 in ADAM15 over-expressing cells reduced Claudin-1 levels. Additionally, downregulation of endogenous ADAM15 expression in T47D cells by shRNA reduced endogenous Claudin-1 expression confirming a role for ADAM15 in regulating Claudin-1 expression. The PI3K/Akt/mTOR pathway was involved in regulating Claudin-1 expression downstream of ADAM15. Immunofluorescence analysis of MDA-MB-231 ADAM15A expressing cells showed Claudin-1 at cell-cell junctions, in the cytoplasm and nuclei. ADAM15 co-localised with Claudin-1 and ZO1 at cell-cell junctions. Immunoprecipitation analysis demonstrated complex formation between ADAM15 and ZO1/ZO2. These findings highlight the importance of ADAM15 Intra Cellular Domain-mediated interactions in regulating substrate selection and breast cancer cell phenotype

Alternative initiation and splicing in dicer gene expression in human breast cells

INTRODUCTION: Dicer is a ribonuclease that mediates RNA interference both at the transcriptional and the post-transcriptional levels. Human dicer gene expression is regulated in different tissues. Dicer is responsible for the synthesis of microRNAs and short temporal (st)RNAs that regulate the expression of many genes. Thus, understanding the control of the expression of the dicer gene is essential for the appreciation of double-stranded (ds)RNA-mediated pathways of gene expression. Human dicer mRNA has many upstream open reading frames (uORFs) at the 5'-leader sequences (the nucleotide sequence between the 5'-end and the start codon of the major ORF), and we studied whether these elements at the 5'-leader sequences regulate the expression of the dicer gene. METHOD: We determined the 5'-leader sequences of the dicer mRNAs in human breast cells by 5'-RACE and S1-nuclease protection analysis. We have analyzed the functions of the 5'-leader variants by reporter gene expression in vitro and in vivo. RESULTS: We found that the dicer transcripts in human breast cells vary in the sequence of their 5'-leader sequences, and that alternative promoter selection along with alternative splicing of the 5'-terminal exons apparently generate these variations. The breast cell has at least two predominant forms of dicer mRNAs, one of which has an additional 110 nucleotides at the 5'-end. Sequence comparison revealed that the first 80 nucleotides of these mRNA isoforms are encoded by a new exon located approximately 16 kb upstream of the reported start site. There are 30 extra nucleotides added to the previously reported exon 1. The human breast cells studied predominantly express two 5'-leader variants of dicer mRNAs, one with the exons 2 and 3 (long form) and the other without them (short form). By reporter gene expression analysis we found that the exon 2 and 3 sequences at the 5'-leader sequences are greatly inhibitory for the translation of the mRNA into protein. CONCLUSION: Dicer gene expression in human breast cells is regulated by alternative promoter selection to alter the length and composition of the 5'-leader sequence of its mRNA. Furthermore, alternative splicing of its exon 2 and 3 sequences of their pre-mRNA creates a more translationally competent mRNA in these cells

Polyamine Sharing between Tubulin Dimers Favours Microtubule Nucleation and Elongation via Facilitated Diffusion

We suggest for the first time that the action of multivalent cations on microtubule dynamics can result from facilitated diffusion of GTP-tubulin to the microtubule ends. Facilitated diffusion can promote microtubule assembly, because, upon encountering a growing nucleus or the microtubule wall, random GTP-tubulin sliding on their surfaces will increase the probability of association to the target sites (nucleation sites or MT ends). This is an original explanation for understanding the apparent discrepancy between the high rate of microtubule elongation and the low rate of tubulin association at the microtubule ends in the viscous cytoplasm. The mechanism of facilitated diffusion requires an attraction force between two tubulins, which can result from the sharing of multivalent counterions. Natural polyamines (putrescine, spermidine, and spermine) are present in all living cells and are potent agents to trigger tubulin self-attraction. By using an analytical model, we analyze the implication of facilitated diffusion mediated by polyamines on nucleation and elongation of microtubules. In vitro experiments using pure tubulin indicate that the promotion of microtubule assembly by polyamines is typical of facilitated diffusion. The results presented here show that polyamines can be of particular importance for the regulation of the microtubule network in vivo and provide the basis for further investigations into the effects of facilitated diffusion on cytoskeleton dynamics

Disruption of Spectrin-Like Cytoskeleton in Differentiating Keratinocytes by PKCδ Activation Is Associated with Phosphorylated Adducin

Spectrin is a central component of the cytoskeletal protein network in a variety of erythroid and non-erythroid cells. In keratinocytes, this protein has been shown to be pericytoplasmic and plasma membrane associated, but its characteristics and function have not been established in these cells. Here we demonstrate that spectrin increases dramatically in amount and is assembled into the cytoskeleton during differentiation in mouse and human keratinocytes. The spectrin-like cytoskeleton was predominantly organized in the granular and cornified layers of the epidermis and disrupted by actin filament inhibitors, but not by anti-mitotic drugs. When the cytoskeleton was disrupted PKCδ was activated by phosphorylation on Thr505. Specific inhibition of PKCδ(Thr505) activation with rottlerin prevented disruption of the spectrin-like cytoskeleton and the associated morphological changes that accompany differentiation. Rottlerin also inhibited specific phosphorylation of the PKCδ substrate adducin, a cytoskeletal protein. Furthermore, knock-down of endogenous adducin affected not only expression of adducin, but also spectrin and PKCδ, and severely disrupted organization of the spectrin-like cytoskeleton and cytoskeletal distribution of both adducin and PKCδ. These results demonstrate that organization of a spectrin-like cytoskeleton is associated with keratinocytes differentiation, and disruption of this cytoskeleton is mediated by either PKCδ(Thr505) phosphorylation associated with phosphorylated adducin or due to reduction of endogenous adducin, which normally connects and stabilizes the spectrin-actin complex

The role of prostaglandin E2 (PGE 2) in toll-like receptor 4 (TLR4)-mediated colitis-associated neoplasia

<p>Abstract</p> <p>Background</p> <p>We have previously found that TLR4-deficient (TLR4-/-) mice demonstrate decreased expression of mucosal PGE ₂and are protected against colitis-associated neoplasia. However, it is still unclear whether PGE ₂is the central factor downstream of TLR4 signaling that promotes intestinal tumorigenesis. To further elucidate critical downstream pathways involving TLR4-mediated intestinal tumorigenesis, we examined the effects of exogenously administered PGE ₂in TLR4-/- mice to see if PGE ₂bypasses the protection from colitis-associated tumorigenesis.</p> <p>Method</p> <p>Mouse colitis-associated neoplasia was induced by azoxymethane (AOM) injection followed by two cycles of dextran sodium sulfate (DSS) treatment. Two different doses of PGE ₂(high dose group, 200 μg, n = 8; and low dose group, 100 μg, n = 6) were administered daily during recovery period of colitis by gavage feeding. Another group was given PGE ₂during DSS treatment (200 μg, n = 5). Inflammation and dysplasia were assessed histologically. Mucosal Cox-2 and amphiregulin (AR) expression, prostanoid synthesis, and EGFR activation were analyzed.</p> <p>Results</p> <p>In control mice treated with PBS, the average number of tumors was greater in WT mice (n = 13) than in TLR4-/- mice (n = 7). High dose but not low dose PGE ₂treatment caused an increase in epithelial proliferation. 28.6% of PBS-treated TLR4-/- mice developed dysplasia (tumors/animal: 0.4 ± 0.2). By contrast, 75.0% (tumors/animal: 1.5 ± 1.2, P < 0.05) of the high dose group and 33.3% (tumors/animal: 0.3 ± 0.5) of the low dose group developed dysplasia in TLR4-/- mice. Tumor size was also increased by high dose PGE ₂treatment. Endogenous prostanoid synthesis was differentially affected by PGE ₂treatment during acute and recovery phases of colitis. Exogenous administration of PGE ₂increased colitis-associated tumorigenesis but this only occurred during the recovery phase. Lastly, PGE ₂treatment increased mucosal expression of AR and Cox-2, thus inducing EGFR activation and forming a positive feedback mechanism to amplify mucosal Cox-2.</p> <p>Conclusions</p> <p>These results highlight the importance of PGE ₂as a central downstream molecule involving TLR4-mediated intestinal tumorigenesis.</p